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MU operation

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MU operation
Posted by daveklepper on Monday, July 23, 2012 5:10 AM

I am answering a personal email posting in this general forum because Ithink what I have to say is of general interest.

The question had to do with the positioning of married pairs and single cars in particular order for passenger car mu operaton, and the answer is that except in very special cases, like a North Shore observation car, mu operaton allowed placement of cars in any random order with successful operation.  Some operators, like the IRT in New York City, preferred a motor-trailer-motor-trailer-moter, type of arrangement, for smoothness in operation and ease of train handling, but the train would still run with motor-motor-trailer-trailer-motor, for example.   And don't assume that a married pair means a motor and a trailer paired.  In the case of LIRR and NJT and MN, all axles on all mu cars are powered.    Married pairs mean that the B end of the two cars, the ends facing each other within the married pair, lack control cabs, and the Bends are often connected with drawbars instead of couplers.   Often one of the two cars will have all the batteries and the other the compressors, etc.        But random order is possible with successful operation.

In understand the South Shore has genuine trailers, in the single level invetory, and these are usually allocated only one to any specific train, not of course at the head end.  (Or do they have controls?)

 

The same is true in most cases for diesels.   Assuming their are cable sockets for jumpers in the noese, A units can run elephant style or back-to-back.    YOu can even have a back to bakc A combination with a B until behind, although I never saw this, but it would work.    There were aprtiuclar transition problems associated with specific lash-ups that had to be avoided, but these were all special cases.   Similarly, except for Baldwins, units of different manufacturers would usualy work together and still do.

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Posted by Falcon48 on Monday, July 23, 2012 9:26 PM

daveklepper

I am answering a personal email posting in this general forum because Ithink what I have to say is of general interest.

The question had to do with the positioning of married pairs and single cars in particular order for passenger car mu operaton, and the answer is that except in very special cases, like a North Shore observation car, mu operaton allowed placement of cars in any random order with successful operation.  Some operators, like the IRT in New York City, preferred a motor-trailer-motor-trailer-moter, type of arrangement, for smoothness in operation and ease of train handling, but the train would still run with motor-motor-trailer-trailer-motor, for example.   And don't assume that a married pair means a motor and a trailer paired.  In the case of LIRR and NJT and MN, all axles on all mu cars are powered.    Married pairs mean that the B end of the two cars, the ends facing each other within the married pair, lack control cabs, and the Bends are often connected with drawbars instead of couplers.   Often one of the two cars will have all the batteries and the other the compressors, etc.        But random order is possible with successful operation.

In understand the South Shore has genuine trailers, in the single level invetory, and these are usually allocated only one to any specific train, not of course at the head end.  (Or do they have controls?)

 

The same is true in most cases for diesels.   Assuming their are cable sockets for jumpers in the noese, A units can run elephant style or back-to-back.    YOu can even have a back to bakc A combination with a B until behind, although I never saw this, but it would work.    There were aprtiuclar transition problems associated with specific lash-ups that had to be avoided, but these were all special cases.   Similarly, except for Baldwins, units of different manufacturers would usualy work together and still do.

I'm not sure about the South Shore's current rolling stock, but many MU operators used "control trailers" (examples in the Chicago area included the North Shore, CA&E, Chicago Rapid Transit).  These were true, unpowered trailers which were not "married" to a powered car,  But they had contols which allowed them to be used as the head car of a train

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Posted by daveklepper on Thursday, July 26, 2012 4:35 AM

You are absolutely correct.   The oldest operable rapid transit car in existance, Pay Car G or the Manhattan Elevated - Interboro Rapid Transit at the Shore Line Torlley Musuem is such an example.   It has no motors, but has controls, which have been modified slightly so it can control one or two motored Brooklyn elevated cars in the musuem and run as the cotrol trailer of a train.  I believe the car was originally built as a steam hauled trailer in 1876 and continued as a money car for the Third Avenue Elevated until about 1950.    Its electrification did not include motors, but did include controls, electric lights, and heat.   But nearly all Brooklyn and Manhattan elevated trailer cars did not have controls.   Another variety are "blind motors", cars with motors but without controls.   The C&AE and the North Shore had control trailers, but only the North Shore also had blind motors at one time, before WWII.  

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Posted by CSSHEGEWISCH on Thursday, July 26, 2012 8:50 AM

LIRR also had blind motors in its fleet of MU cars delivered in the early 1950's.  South Shore's current fleet of MU cars includes trailers numbered in the 100 series.  They do not have controls but they do have pantographs to provide power for lighting, HVAC and other auxiliaries.

The daily commute is part of everyday life but I get two rides a day out of it. Paul
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Posted by artpeterson on Thursday, July 26, 2012 10:41 AM

On the CRT, the Metropolitan Division had no-control, single-control and double-end control trailers.  Further in CRT days, to ease the job of the clerks in recording car mileage the trailers had certain motors they were to work with when multiple-car operation was required.  This meant that a motor that might be used on the midnight had to be reunited with the same trailer for service the next day, making the yard foreman's job a huge chess game.  As info, Art

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